Temperature-compensating mechanism.



A. BONNET. TEMPERATURE GOMPENSATING MECHANISM. APPLICATION nun 111111.14, 1910.

968,235, Patented Aug. 23, 1910.

v 15595. L M67ZZ07Y l 4 r W affafzmxfiwmei A I mwwz.

1n: mamas PETERS cm'iunmamu, n. c

UNITED STATES PATENT OFFICE.

ARTHUR BONNET, OF CHICAGO, ILLINOIS, ASSIGNOR TO LINCOLN WATCH & JEWELRY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF WEST VIRGINIA.

TEMPERATURE-COMPENSATING- MECHANISM.

Specification of Letters Patent.

Patented Aug. 23, 1910.

Application filed March 14, 1910. Serial No. 549,280.

To all 107mm it may concern:

Be it known that I, ARTHUR BONNET, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Temperature-Compensating Mechanism, of which the following is a specification.

My invention relates to temperature compensating mechanism, and has particular reference to a mechanism which is adapted to be used in connection with the hair springs of watches.

Accordin to the usual construction which is employed in watches, as the temperature increases, the hair spring will be elongated thereby and the tension on the hair spring will correspondingly be decreased, The result will be that as the tension decreases, the watch will be made to run slower. Similarly when the temperature decreases, the tension on the hair spring will increase and the watch will run faster. It is thus evident that there will be a strong tendency for the watch to run too rapidly in winter and too slowly in summer unless some temperature compensating mechanism is provided.

According to the usual construction which is employed in watches one end of the hair spring is attached to a post which is rigidly mounted on the main frame work connected with the plate of the watch. The other end of the spring is attached to the balance wheel and causes the same to oscillate back and forth, the necessary power to continue this operation being supplied by means of an escapement.

In order to regulate the tension of the hair spring, and thus either increase or decrease the speed of oscillation of the balance wheel, a slotted pin is usually provided, and through the slot one strand or convolution of the hair spring passes. In place of using the pin with the slot therein, two pins are often employed, and the strand of the hair spring passes between them. By moving these regulating pins in the direction away from the end of the hair spring, which is rigidly attached to the post mounted on the main frame of the watch, it will be apparent that the effective 0 erating length of the hair spring will be re uced inasmuch as the portion of the spring held by the pins will be prevented from uncoiling when the balance wheel is moved in one direction, and

coiling up when it is moved in the opposite direction. The farther the regulating pins are moved from the post to which the end of the hair spring is attached, therefore, the faster the balance wheel will be caused to oscillate. Now when the temperature rises, the hair spring will increase in length and the tension correspondingly will decrease. In order to have the tension remain the same as before, the regulating pins must be moved away from the post to which the outer end of the hair spring is attached. Again, when the temperature drops, the regulating pins must be moved toward the post, and thus compensate for the increased tension. It is the means of automatically accomplishing this result which forms the subject matter of my invention,

The regulating pins are mounted on a movable frame with which the regulator arm is integral. Bearing against one side of this arm is a spring which tends to force the same in the direction which will cause the regulating pins to be moved toward the outer end of the hair spring. Bearing on the other side of the regulator arm, is a tension screw by means of which the position of the regulating pins may be ad justed. This tension screw should be made of such material that as the temperature increases, the screw will elongate and force the regulator arm against the tension of the spring, moving the tension regulating pins away from the outer end of the hair spring, thereby compensating for the decreased tension which will result in the hair spring from the rise of temperature. Similarly when the temperature drops the tension screw will contract, and the spring associated with the regulator arm will move this arm so that the regulating pins will be moved toward the outer end of the hair spring, thus compensating for the increased tension which results in the hair spring. It will be evident that in order to have this compensation correct for all temperatures, a certain fixed relation must exist between the coeflicient of expansion of the hair spring, and the coeiiicient of expansion of the tension screw. It will be clear that to obtain the desired result, the hair spring should be so adjusted in the factory that the regulator arm should occupy a predetermined position which is preferably at the center of the regulating scale, thus causing a predetermined length of the tension screw to be effective in making the temperature compensation. I have found that the de sired result is obtained by constructing the tension screw of steel which is softer, that is, with a lower carbon content than that of the tempered steel of which the hair spring is made.

The various advantages of my invention will be apparent from the accompanying drawings in which:

Figure 1 is a plan view showing the parts essential to my invention mount-ed on the main watch plate. Fig. 2 is an elevation view of the tension screw.

Mounted on the watch plate 5, and attached thereto by means of the screw 6, is the balance wheel support 7. Mounted near the inner end of support 7 is the disk 8, held in position by the screws 9, and having at its center the jewel bearing 10. The balance wheel 11 is provided with a shaft, the ends of which operate in the bearing 10 and the corresponding bearing in the plate 5. Integral with the support 7 is a projection 12, extending downwardly from which is a pin or post 13, securely held in posi tion by the set-screw let. The inner end of the hair spring 15, is firmly attached to the balance wheel in a manner which is well understood in the art, and the outer end to the post 13.

Inclosing the disk 8 is the frame 16, integral with which are the projection 17 and the regulator arm 18. Extending clownwardly from the projection 17, are two pins 19 which hold between them the outward strand or convolution of the hair spring 15.

Mounted on the support 7 by means of the screw 20 and the pin 21, is a spring 22 which bears against the left hand side of the arm 18. The tension screw 24: bears against the opposite side of the arm 18, this tension screw being mounted between the support 7 and the plate 23 with which it has a threaded engagement. The groove 25 is provided in the support 7, this groove being for the purpose of accommodating a slight downward projection on the side of the regulator arm 18, the end of screw 2 1 having engagement wit-h this extension. For the sake of simplicity I have not shown this downward extension in the drawing.

Having thus described the construction of the mechanism which comprises my invention, its operation may now be readily understood: The tension screw 2 1 is adjust ed so that the regulator arm 18 will be brought to the desired position in which it is found that the watch keeps the best time, the factory adjustment, as explained above, causing this position to be at approximately the center of the regulating scale. Now let us suppose that the temperature rises. The hair spring will expand and its tension would thereby be decreased if the regulating pins 19 remain in the same position. lVith the expansion of the hair spring 15, however, a proportional expansion of the tension screw 24 takes place and the regulator arm 18 is thereby moved toward the left, the frame work 16 with which the arm 18 is integral being rotated about the disk 8 and the projection 17, carrying the regulating pins 19, being moved toward the right. The tension on the hair spring 15 is consequently increased so that it remains the same as the tension which existed before the rise of temperature occurred. Correspondingly if the temperature drops, the tension screw 24: will contract and the spring 22 will force the regulator arm 18 to the right moving the projection 17, and the regulating pins 19 to the left a sufficient distance to compensate for the increased tension on the hair spring 15 which was caused by the lowering of the temperature.

Although I have described a low carbon steel as the preferred material of which to construct the tension screw, I have found that many other materials may be satisfactorily used to accomplish the same result. Among these may be mentioned brass, bronze and various alloys containing iron.

It will also be apparent that many changes may be made in the exact construction which I have just described without departing from the spirit of my invention.

WVhat I claim as new and desire to cover by United States Letters Patent is:

In a temperature compensating device for watches, the combination with the hair spring, of means for regulating the tension of said spring, and a tension screw having a different composition from said spring, said tension screw adapted to expand and contract by the action of the varying temperature, thereby automatically compensating for the corresponding difierences of tension of said spring, substantially as described.

ARTHUR BONNET.

Witnesses HENRY M. I-IUXLEY, M. ROBERTSON. 

